Add React and TS to webpacker; add react-rails gem

config/webpack/environment.js

@@ -1,6 +1,8 @@
 const { environment } = require('@rails/webpacker')
+const typescript =  require('./loaders/typescript')
 const webpack = require('webpack')
 
+environment.loaders.prepend('typescript', typescript)
 environment.plugins.append(
   'Provide',
   new webpack.ProvidePlugin({